1. Field of the Invention
This invention relates to a pilot fuel injection valve for an internal combustion engine and more specifically to a logic system for controlling the availability of high pressure fuel in the metering sections of the valve.
2. Description of the Prior Art
The concept of pilot fuel injection is known in the prior art. U.S. Pat. application Ser. No. 403,308, filed Oct. 3, 1973, now abandoned and division thereof Ser. No. 689,391, filed May 24, 1976 and assigned to the assignee of this application, discloses a spool type, dual valve for metering pilot and main fuel charges to the cylinders of an engine. A mechanical fuel distributor controls the availability of unmetered high pressure fuel to the spools. The mechanical fuel distributor connects the metering portion of the spools to a source of unmetered high pressure fuel when the spools are moving from an unactuated position to an actuated position. The spools meter fuel while moving between the positions; no fuel is metered in either position. The mechanical fuel distributor then blocks the connection between the source and the spools to prevent the metering of a second fuel charge while the spools are being returned to their unactuated positions. The mechanical fuel distributor adds cost and complexity to the fuel injection system.